Posted on May 17, 2011 at 14:04>>please help me....
Man you really need to help yourself by using the libraries and example code rather than try to bit bang the registers manually. That might be workable once you have a better understanding of the hardware, but If you're just starting you are making life more difficult than it needs to be.
You need to be enabling the PLL, and waiting for it to attain lock BEFORE selecting it as a source. If the source to the PLL is the HSE, you need to power that up and have it stabilize prior to gating it into the PLL. You also need to get the dividers and prescalers for the other buses to legal settings BEFORE switching in a clock which will exceed them. ie APB1 has a 36 MHz max, and you will need additional wait states for the flash to function properly above 24 and 48 MHz thresholds.
